[MVP] Auto-detect API keys from common locations

[mikejmorgan-ai]

Zero Config API Keys

Automatically find API keys without user setting env vars:

$ cortex install nginx

🔑 Found Anthropic API key in ~/.config/anthropic
📦 Installing nginx...

Check Locations (in order)

1. Environment: ANTHROPIC_API_KEY, OPENAI_API_KEY
2. ~/.cortex/.env
3. ~/.config/anthropic (Claude CLI location)
4. ~/.config/openai
5. .env in current directory

Requirements

• Check all locations on startup
• Cache found key location
• Prompt to save if entered manually
• Show which provider being used

Fallback

If no key found:

No API key found. Enter your Anthropic or OpenAI key:
> sk-ant-...
Save to ~/.cortex/.env? [Y/n]

Bounty: $15 now (+$15 match after funding)

Total: $30 when we close our funding round.